Methods for anchoring suture to bone

ABSTRACT

Methods and devices are provided for anchoring suture to bone. In one exemplary embodiment, a cannulated suture anchor is provided and it includes a suture-engaging member formed therein and configured to receive a suture therearound such that trailing ends of the suture can extend through the suture anchor. The suture anchor can also include at least a proximal portion having dual threads to facilitate engagement with bone. The present invention also provides exemplary sutures and drivers that can be used with the various methods and devices disclosed herein, or with other methods and devices known in the art.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/855,728, now U.S. Pat. No. 8,702,754, filed Sep. 14, 2007and entitled “METHODS FOR ANCHORING SUTURE TO BONE” and U.S. patentapplication Ser. No. 11/855,670, now U.S. Pat. No. 8,882,801, filed Sep.14, 2007 and entitled “DUAL THREAD CANNULATED SUTURE ANCHOR”, which arehereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention generally relates to medical devices andprocedures, and more particularly to systems and methods for attachingsoft tissue to bone.

BACKGROUND OF THE INVENTION

The complete or partial detachment of ligaments, tendons and/or othersoft tissues from their associated bones within the body are relativelycommonplace injuries, particularly among athletes. Such injuries aregenerally the result of excessive stresses being placed on thesetissues. By way of example, tissue detachment may occur as the result ofan accident such as a fall, over-exertion during a work-relatedactivity, during the course of an athletic event, or in any one of manyother situations and/or activities.

In the case of a partial detachment, the injury will frequently healitself, if given sufficient time and if care is taken not to expose theinjury to further undue stress. In the case of complete detachment,however, surgery may be needed to re-attach the soft tissue to itsassociated bone or bones. Numerous devices are currently available tore-attach soft tissue to bone. Examples of such currently-availabledevices include screws, staples, suture anchors, and tacks. In softtissue re-attachment procedures utilizing screws, the detached softtissue is typically moved back into its original position over the bone.Then the screw is screwed through the soft tissue and into the bone,with the shank and head of the screw holding the soft tissue to thebone. Similarly, in soft tissue re-attachment procedures utilizingstaples, the detached soft tissue is typically moved back into itsoriginal position over the bone. Then the staple is driven through thesoft tissue and into the bone, with the legs and bridge of the stapleholding the soft tissue to the bone.

In soft tissue re-attachment procedures utilizing suture anchors, ananchor-receiving hole is generally first drilled in the bone at thedesired point of tissue re-attachment. Then a suture anchor is deployedin the hole using an appropriate installation tool. This effectivelylocks the suture to the bone, with the free end(s) of the sutureextending out of the bone. The free ends of the suture are passedthrough or around the soft tissue and are used to tie the soft tissuesecurely to the bone.

While current suture anchors are effective in anchoring soft tissue tobone, one drawback with current devices is that the suture anchor musthave a head with a length that is sufficient to withstand a torqueapplied thereto by a driver. As a result of the increased length, thesuture anchor will typically extend at least partially into underlyingsoft cancellous bone in order to position the head beneath the outersurface of the bone. The bone-engaging portion of the suture anchor willthus be mostly disposed within and engaged with cancellous bone, ratherthan cortical bone. This is due to the fact that the cortical bone isonly about 1 mm to 3 mm in length, and the driver head is often longerthan 3 mm. Once implanted, tension applied to the anchor via the suturescan cause the anchor to migrate into the cortical bone and thus the headof the suture anchor can become proud, resulting in a weak fixationamong other problems.

Accordingly, there remains a need for improved methods and devices forattaching soft tissue to bone.

SUMMARY OF THE INVENTION

Methods and devices are provided for anchoring sutures to bone. In oneembodiment, a suture anchor is provided having an elongate body withproximal and distal ends and an inner lumen extending therethrough. Afirst thread extends around the elongate body from the proximal endtoward the distal end of the elongate body, and a second thread extendsaround the elongate body between at least a portion of the first threadsuch that the first and second threads are spaced a distance apart fromone another. In an exemplary embodiment, the elongate body has aconstant root diameter. The suture anchor can also include asuture-engaging member located adjacent to the distal end of theelongate body and positioned such that a suture can be disposedtherearound and trailing ends of the suture can extend through the innerlumen and out of the proximal end of the elongated body.

The first and second threads can have various configurations. In oneembodiment, the first thread can extend from the proximal end to aposition just proximal to the suture-engaging member, and the secondthread can extend from the proximal end and terminate proximal to thefirst thread. In another embodiment, the first and second threads canextend from the proximal end to a position just proximal to thesuture-engaging member such that the first and second threads have alength that is substantially the same. Alternatively, the first threadcan extend from the proximal end to the distal end, and the secondthread can extend from the proximal end and terminate proximal to thefirst thread. In another embodiment, the first and second threads canextend from the proximal end to the distal end such that the first andsecond threads have a length that is substantially the same and thatextends along an entire length of the elongate body.

The suture anchor can also include various other features. For example,the suture anchor can include a distal tip formed on the distal end ofthe suture anchor. The threads can be formed on the distal tip, or thedistal tip can be non-threaded. The tip can also be blunt or it can bepointed to facilitate insertion into a bone hole, and the tip can behollow or solid. In other embodiments, the suture anchor can include aproximal end that is configured to receive a driver. For example, aproximal portion of the inner lumen can have an asymmetrical ornon-circular cross-sectional shape for receiving a driver tool therein.

The suture-engaging member can also have a variety of configurations. Inan exemplary embodiment, the suture-engaging member extends betweenopposed walls of the inner lumen, preferably substantially perpendicularto a longitudinal axis of the lumen. The suture-engaging member can havevarious shapes and sizes. For example, in one embodiment thesuture-engaging member include features, such as scallops, to facilitatepositioning of multiple sutures.

In yet another embodiment, a suture anchor is provided having anelongate body with first and second threads extending from a proximalend toward a distal end of the elongate body, an inner lumen extendinginto a proximal end of the elongate body, and a cut-out formed in asidewall of the elongate body. The cut-out is in communication with theinner lumen and it defines a suture-engaging member extending across theinner lumen and configured such that a suture can extend around thesuture-engaging member and trailing ends of the suture can extendthrough the cannulated body.

In other aspects, a suture anchor is provided having a cannulated bodywith first and second threads extending from a proximal end toward adistal end of the cannulated body, an opening formed in a sidewall ofthe cannulated body and in fluid communication with an inner lumenextending through the elongate body, and a suture-engaging memberextending across the inner lumen and configured such that a suture canextend around the suture-engaging member and trailing ends of the suturecan extend through the cannulated body.

Exemplary suture anchor systems are also provided, and in one embodimentthe system can include a suture anchor having a cannulated body withfirst and second threads extending from a proximal end toward a distalend of the cannulated body, and a suture-engaging member locatedadjacent to the distal end and configured such that a suture can extendaround the suture-engaging member and trailing ends of the suture canextend through the cannulated body. The system can also include a drivertool having a distal end adapted to be inserted into and to engage theproximal end of the suture anchor for driving the suture anchor intobone.

The threads can have various configurations. In one embodiment, thesecond thread can have a distal end that terminates at a locationproximal to a distal end of the first thread. Alternatively, the firstand second threads can have a length that is substantially the same. Thesuture anchor can also include various other features, including thosepreviously discussed above.

Exemplary methods for anchoring suture to bone are also provided. In oneembodiment, a method for anchoring suture to bone includes coupling asuture to a suture anchor such that the suture extends around asuture-engaging member formed in a distal portion of the suture anchorand trailing ends of the suture extend through an inner lumen extendingthrough the suture anchor and out of a proximal end of the sutureanchor. A driver is inserted into the proximal end of the suture anchor,and the driver is rotated to thread the suture anchor into a bone holeto anchor the suture to the bone. In an exemplary embodiment, the sutureanchor includes an opening formed in a sidewall thereof that allowsfluid to flow into the inner lumen of the suture anchor. The sutureanchor can include first and second threads that are spaced axiallyapart from one another and that have the same pitch such that the firstand second threads are driven into bone at the same rate. In oneembodiment, the first and second threads can be formed on at least theproximal portion of the suture anchor such that the first and secondthreads engage cancellous bone. In another embodiment, the first threadcan extend along a distal portion of the suture anchor such that thefirst thread engages cortical and cancellous bone. In yet anotherembodiment, the first and second threads can extend from the proximalend to the distal end of the suture anchor such that the first andsecond threads engage cortical and cancellous bone.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A is a side view of one embodiment of a cannulated suture anchorhaving a proximal portion with a dual threaded region and a singlethreaded region, and a non-threaded distal portion with asuture-engaging member;

FIG. 1B is a perspective view of the cannulated suture anchor of FIG.1A;

FIG. 1C is a cross-sectional view of the cannulated suture anchor ofFIG. 1A;

FIG. 1D is another cross-sectional view of the cannulated suture anchorof FIG. 1A;

FIG. 2A is a side view of another embodiment of a cannulated sutureanchor having a dual threaded proximal portion and a non-threaded distalportion with a suture-engaging member;

FIG. 2B is a perspective view of the cannulated suture anchor of FIG.2A;

FIG. 3A is a side view of yet another embodiment of a cannulated sutureanchor having a proximal portion with a dual threaded region and asingle threaded region, and a non-threaded distal portion with asuture-engaging member and a bone-penetrating tip;

FIG. 3B is a perspective view of the cannulated suture anchor of FIG.3A;

FIG. 3C is a cross-sectional view of the cannulated suture anchor ofFIG. 3A;

FIG. 3D is another cross-sectional view of the cannulated suture anchorof FIG. 3A;

FIG. 4A is a side view of a cannulated suture anchor having a dualthreaded proximal portion and a single threaded distal portion with asuture-engaging member and a bone-penetrating tip according to anotherembodiment;

FIG. 4B is a perspective view of the cannulated suture anchor of FIG.4A;

FIG. 4C is a cross-sectional view of the cannulated suture anchor ofFIG. 4A;

FIG. 4D is another cross-sectional view of the cannulated suture anchorof FIG. 4A;

FIG. 5A is a side view of yet another embodiment of a cannulated sutureanchor having a proximal portion with a dual threaded region and asingle threaded region, a threaded distal portion having a pointed tip,and a scalloped suture-engaging member;

FIG. 5B is a cross-sectional view of the cannulated suture anchor ofFIG. 5A;

FIG. 6 is a perspective view of one embodiment of a driver tool forinserting a suture anchor into bone;

FIG. 7 is a cross-sectional view of another embodiment of a driver toolshown engaged with a suture anchor; and

FIG. 8 is a partially cross-sectional view of the suture anchor of FIG.1A implanted in bone and having three sutures coupled thereto.

DETAILED DESCRIPTION OF THE INVENTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those of ordinary skill in the art will understand that thedevices and methods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

The present invention generally provides methods and devices foranchoring suture to bone. In an exemplary embodiment, a cannulatedsuture anchor is provided and includes a suture-engaging member formedtherein or thereon and configured to receive a suture therearound suchthat trailing ends of the suture can extend through the suture anchor.The use of a cannulated suture anchor allows a driver to be insertedinto the inner lumen of the suture anchor for driving the suture anchorinto bone. Such a configuration will allow the torque strength of thesuture anchor to be maximized due to the increased engagement betweenthe suture anchor and the driver. This in turn will allow the sutureanchor to be formed from a broad range of materials, includingnonabsorbable materials, such as metal or plastic, bioabsorbablematerials, and/or osteoconductive materials. The cannulated sutureanchor is also particularly advantageous as the inner lumen can allowmaterials, such as bone-growth promoting materials, sealants, adhesives,etc., to be introduced therein to facilitate fixation. The suture anchorcan also include at least a proximal portion with dual threadsconfigured to optimize fixation within hard cortical bone, therebydecreasing the risk for migration of the suture anchor. A person skilledin the art will appreciate that, while methods and devices are disclosedherein for anchoring soft tissue to bone, the methods and devices can beused in a variety of other medical procedures for anchoring variousobjects to one another.

FIGS. 1A-1D illustrate one exemplary embodiment of a cannulated sutureanchor 10 for anchoring soft tissue to bone. As shown, the suture anchor10 is in the form of a generally elongate body having proximal anddistal ends 10 a, 10 b with an inner lumen 10 c extending therethrough.At least one bone-engaging surface feature can be formed on at least aportion of an external surface thereof for engaging bone. In theillustrated embodiment, the suture anchor 10 includes a threadedproximal portion 12 a and a non-threaded distal portion 12 b. The sutureanchor 10 also includes a suture-engaging member 14 disposed within theinner lumen 10 c adjacent to the distal end 10 b of the suture anchor10. The suture-engaging member 14 can be adapted to receive one or moresutures therearound such that the suture(s) can extend around thesuture-engaging member 14 and trailing ends of the suture(s) can extendthrough the inner lumen 10 c and out of the proximal end 10 a of thesuture anchor 10.

The suture anchor 10 can be formed from a variety of materials. In anexemplary embodiment, the material has physical properties that aresufficient to allow a driver to be inserted into the inner lumen 10 c ofthe suture anchor 10 and to be used to drive the suture anchor 10 intobone without damaging the suture anchor 10. The properties of thematerial will of course depend on the particular configuration of thesuture anchor 10. For example, the inner lumen 10 c of the suture anchor10 can have a length that maximizes the torque strength of the sutureanchor 10 as well as the amount of surface contact between a driver andthe suture anchor 10, thus allowing weaker materials, such asbioabsorbable and/or osteoconductive materials to be used. A personskilled in the art will appreciate that a variety of other materials,including plastics and metals, can be used to form the suture anchor 10.

The body of the suture anchor 10 can have a variety of configurations,shapes, and sizes. In an exemplary embodiment, the body is configured tobe implanted within a bone tunnel formed in bone, and more preferably ithas a size and shape that allows it to be fully engaged through thethickness of the cortical bone. As indicated above, in the illustratedembodiment the body has a generally elongate cylindrical shape with aninner lumen 10 c extending therethrough. The diameter d₁ of the innerlumen 10 c can vary, but in an exemplary embodiment the diameter d₁ issufficient to receive one or more, and preferably three, pairs ofsutures therethrough. In an exemplary embodiment, the inner lumen 10 chas a diameter d₁ that is in the range of about 1.5 mm to 3.0 mm. Thiswill allow six trailing ends of three sutures having a maximum outerdiameter of about 0.028 inches each to be disposed through the innerlumen 10 c. As further shown in FIGS. 1A-1D, the inner 10 c lumen canextend through the entire length of the suture anchor 10, includingthrough the distal tip as will be discussed in more detail below. Thesuture-engaging member 14 can, however, extend across a portion of thelumen 10 c, as will be discussed in more detail below. In otherembodiments, the lumen 10 c can terminate prior to a substantially solidtip. The tip can be blunt or rounded, as shown, or it can be pointed tofacilitate insertion into a bone tunnel. Other tip configurations can beutilized, as later disclosed herein or as known in the art.

The proximal end 10 a of the body can be head-free, as the cannulatedconfiguration of the body allows a driver to be inserted into the innerlumen 10 c to drive the suture anchor 10 into bone. While varioustechniques can be used to facilitate engagement between the inner lumen10 c and a driver mechanism, in an exemplary embodiment the inner lumen10 c, or at least a portion thereof, has an asymmetrical or non-circularshape that complements a corresponding asymmetrical or non-circularshape of a driver. The asymmetrical portion preferably extends along asubstantial length of the inner lumen 10 c so as to maximum surfacecontact between a driver and the suture anchor 10. By way ofnon-limiting example, FIGS. 1C and 1D illustrate a hexagonalcross-sectional shape formed in the inner lumen 10 c for receiving adriver having a corresponding hexagonal drive tip. The hexagonalcross-section extends from the proximal-most end 10 a of the sutureanchor 10 and terminates just proximal to the proximal end of a cut-out16, as will be discussed in more detail below. Exemplary drivers arediscussed in more detail below, and are also disclosed in commonly-ownedU.S. application Ser. No. 11/555,545 filed on Nov. 1, 2006 and entitled“Cannulated Suture Anchor,” U.S. application Ser. No. 11/555,557 filedon Nov. 1, 2006 and entitled “Suture Anchor With Pulley,” and U.S.application Ser. No. 11/555,568 filed on Nov. 1, 2006 and entitled“Wired Sutures,” all of which are hereby incorporated by reference intheir entireties.

As further shown in FIGS. 1A-1D, the body can also include one or morebone-engaging surface features formed thereon and adapted to engagebone. While various surface features can be used, such as teeth, ridges,protrusions, etc., in an exemplary embodiment the body can include oneor more threads extending therearound, and more preferably the threadsare formed on at least a proximal portion of the body to provideenhanced fixation with hard cortical bone to prevent migration of thesuture anchor when implanted. As shown in FIGS. 1A-1D, the body includesa threaded proximal portion 12 a having a first and second threads 18 a,18 b extending therearound and a non-threaded distal portion 12 b. Thefirst thread 18 a originates at the proximal end 10 a of the body and itterminates just proximal to the suture-engaging member 14. Theparticular location at which the first thread 18 a terminates can varydepending on the particular configuration of the suture anchor 10, aswell as the configuration of the tip. As will be discussed in moredetail below, the illustrated suture anchor 10 can include a cut-out 16formed in the distal end 10 b thereof and the first thread 18 a canterminate just proximal to the proximal end of the cut-out 16. As aresult, the first thread 18 a extends along about 75% of the length ofthe suture anchor 10. A person skilled in the art will appreciate,however, that the length of the first thread 18 a can vary. As furthershown in FIGS. 1A-1D, the body can also include a second thread 18 bextending between the first thread 18 a. The second thread 18 b canextend over only a portion of the body, or over the entire length of thebody, including or excluding the distal tip, as will be discussed inmore detail below. As shown in FIGS. 1A-1D, the second thread 18 bextends along only a proximal-most portion of the body, and itterminates proximal to the first thread 18 a. The illustrated secondthread 18 b thus extends over about 25% of the length of the sutureanchor 10. As a result, the illustrated suture anchor 10 includes athreaded proximal portion 12 a with a dual threaded proximal region anda single threaded distal region.

While the position of the second thread 18 b relative to the firstthread 18 a can vary, in an exemplary embodiment, as shown, the secondthread 18 b extends between the first thread 18 a and the threads 18 a,18 b are spaced equidistant apart from one another along the axis A ofthe suture anchor 10, i.e., the threads 18 a, 18 b are axially aligned.The first and second threads 18 a, 18 b can also have the same ordifferent configurations, but in an exemplary embodiment the first andsecond threads 18 a, 18 b are identical and have the same shape andsize, including the same pitch. This will allow the first and secondthreads 18 a, 18 b to simultaneously cut independent courses (paths)through bone. While the pitch can vary depending on the particularconfiguration of the suture anchor as well as the intended use, in anexemplary embodiment the pitch is in the range of about 8 TPI to 20 TPI,and more preferably the pitch is about 15 TPI. The first and secondthreads 18 a, 18 b can also be aligned radially with one another, oralternatively the second thread 18 b can be radially offset from thefirst thread 18 a such that one of the threads, e.g., the first thread18 a, engages bone prior to the other thread, e.g., the second thread 18b, to facilitate insertion.

The geometry of each thread 18 a, 18 b can also vary, and the threads 18a, 18 b can have a constant thickness between the root and crest, or thethickness can decrease from the root to the crest as shown. The shape ofthe crest can also vary. As shown in FIGS. 1A-1D, the threads 18 a, 18 beach have a v-shaped configuration with opposed surfaces that extend atabout 40° and with a flat crest. Such a configuration facilitatesengagement with bone, thereby preventing suture migration when theanchor 10 is implanted.

As further shown in FIGS. 1A-1D, the suture anchor 10 can also have aminor or root diameter dmin that remains constant along the entirelength thereof, or at least along the threaded portion. The majordiameter dmax can also remain constant along the entire length of thesuture anchor 10. While the particular dimensions will vary depending onthe size of the suture anchor and the intended application, in anexemplary embodiment the suture anchor 10 has major and minor diametersdmax, dmin that differ by about 1-2 mm, and more preferably about 1.5mm. For example, the major diameter can be about 5.5 mm, and the minordiameter can be about 4 mm. A person skilled in the art will appreciatethat the major and/or minor diameters can also vary, and they can taperalong a portion or along the entire length of the suture anchor 10.

As previously indicated above, the suture anchor 10 can also include asuture-engaging member 14. The suture-engaging member 14 can have avariety of configurations, but in an exemplary embodiment it is adaptedto engage one or more sutures that extend through the inner lumen 10 cof the suture anchor 10. As shown in FIGS. 1A-1D, the suture-engagingmember 14 is in the form of a post or elongate member that extendstransversely across the inner lumen 10 c between opposed inner sidewallsof the suture anchor 10. The angular orientation of the suture-engagingmember 14 relative to the longitudinal axis A of the suture anchor 10can vary, but in an exemplary embodiment the suture-engaging member 14extends substantially perpendicular to the longitudinal axis A of theanchor 10. The location of the suture-engaging member 14 can also vary,but in an exemplary embodiment the suture-engaging member 14 ispositioned at or adjacent to the distal end 10 b of the suture anchor10. In the embodiment shown in FIGS. 1A-1D, the suture-engaging member14 is located just proximal to the distal-most end 10 b of the sutureanchor 10 so as to form a suture-seating groove 19 in the distal-mostend of the suture anchor 10. This recessed configuration of thesuture-engaging member 14 can allow a suture(s) disposed around thesuture-engaging member 14 to sit flush or sub-flush with the distal end10 b of the suture anchor 10 such that the suture(s) will not interferewith insertion of the suture anchor 10 into bone. The location of thesuture-engaging member 14 near the distal end 10 b is also advantageousas it allows the remainder of the lumen extending proximally from thesuture-engaging member 14 to receive the driver. A person skilled in theart will appreciate that the suture-engaging member 14 can be integrallyformed with the suture anchor 10, i.e., the suture anchor 10 andsuture-engaging member 14 can be molded as a single unit or formed froma single piece of material, or the suture-engaging member 14 can befixedly or removably mated to the suture anchor 10.

As further shown in FIGS. 1A-1D, in order to facilitate positioning of asuture(s) around the suture-engaging member 14, the suture anchor 10 caninclude one or more cut-outs formed in a sidewall thereof adjacent tothe suture-engaging member 14. As best shown in FIGS. 1A and 1B, in anexemplary embodiment the suture anchor 10 includes a cut-out 16 thatbegins just proximal to the location of the suture-engaging member 14,and that extends around the distal end 10 b of the suture anchor 10 suchthat the suture anchor 10 includes opposed cut-outs or openings formedon opposed sides of the suture-engaging member 14 and a distal cut-outthat defines the suture-seating groove 19 for seating a suture(s). Thecut-out 16 can also define opposed distal arms 11 a, 11 b on the sutureanchor 10 that are spaced a distance apart from one another and thathave the suture-engaging member 14 extending therebetween.

A person skilled in the art will appreciate that the particular locationand configuration of the cut-out 16 can define the particular locationand configuration of the suture-engaging member 14, as the cut-out 16can be formed during manufacturing to create the suture-engaging member14. Alternatively, the particular location and configuration of theopposed arms 11 a, 11 b can define the particular location andconfiguration of the cut-out 16, as the shape and size of the arms 11 a,11 b defines the shape and size of the cut-out 16. The location of thesuture-engaging member 14 relative to the cut-out 16 and/or arms 11 a,11 b will also define the configuration of the distal end of the sutureanchor 10, and whether the suture anchor 10 includes a distal groove 19for seating a suture(s).

A person skilled in the art will also appreciate that thesuture-engaging member 14 can have a variety of other configurations,and that it can be fixed or movable, e.g., rotatable and/or slidable.Various exemplary configurations are disclosed herein, and in moredetail in the commonly-owned U.S. applications previously referencedherein.

As indicated above, while FIGS. 1A-1D illustrate a second thread 18 bhaving a length that is less than a length of the first thread 18 a, inother embodiments the first and second threads can have the same length.FIGS. 2A-2B illustrate another embodiment of a suture anchor 30 havingfirst and second threads 28 a, 28 b that have the same length. Inparticular, the first and second threads 28 a, 28 b originate at theproximal end 20 a and they both terminate at a location just proximal tothe suture-engaging member 24, or to the cut-out 26 formed in the body.The first and second threads 28 a, 28 b thus extend along about 75% ofthe length of the suture anchor 20. Such a configuration is particularlyadvantageous as the dual threads will improve fixation, especiallywithin the cancellous bone which is engaged by the proximal portion 22 aof the anchor. The distal portion 22 b of the anchor 20 can benon-threaded, and can have the same configuration as previouslydiscussed with respect to FIGS. 1A-1D, or it can have a variety of otherconfigurations as discussed herein or known in the art.

In yet another embodiment, shown in FIGS. 3A-3D, the suture anchor 30can include a pointed tip 33 to facilitate penetration into bone. Asshown, the distal tip 33 can have a solid, pointed configuration, and itcan form the distal-most end of the suture anchor 30. Thesuture-engaging member 34 can thus be positioned proximal to the distaltip 33, and the cut-out 36 can be in the form of a cavity extendingthrough opposed walls of the suture anchor 30, as best shown in FIGS. 3Cand 3D. The remainder of the suture anchor 30 can be similar to theanchor previously discussed with respect to FIGS. 1A-1D. In general, thesuture anchor 30 can include a first thread 38 a that extends from theproximal end 30 a to a position just proximal to the cut-out 36, and asecond thread 38 b that is disposed between the first thread 38 a andthat extends from the proximal end 30 a and terminates proximal to thefirst thread 38 a.

Alternatively, the threads can extend along the entire length of thesuture anchor. FIGS. 4A-4D illustrate another embodiment of a sutureanchor 40 having a first thread 48 a that extends along the entirelength from the proximal end 40 a to the distal end 40 b. The firstthread 48 a thus extends toward and can run-out at the pointed tip 43.The second thread 48 b can extend along only a proximal portion of theanchor 40, as shown in FIGS. 4A-4D, or it can alternatively likewiseextend along the entire length. A person skilled in the art willappreciate that the particular configurations of the threads, as well asthe configuration of the distal tip, can vary and virtually andcombination of features can be combined to form an anchor as may bedesired. As further shown in FIGS. 4A-4D, in order to allow the thread48 a to extend along the distal-most portion, i.e., to extend distallybeyond the cut-out 46 and suture engaging member 44, the cut-out 46 andsuture-engaging member 44 can be located more toward the mid-portion ofthe anchor. As a result, the cut-out 46 extends through the threads. Asis also shown in FIGS. 4A-4D, the portion of the body located distal tothe cut-out 46 can have a root or minor diameter d_(r) that is less thanthe root or minor diameter d_(R) of the remaining proximal portion ofthe anchor. This will form a smaller tip to facilitate impaction intobone.

FIGS. 5A and 5B illustrate another embodiment of a suture anchor 50. Inthis embodiment, the suture anchor 50 is similar to anchor 40, exceptthat the suture-engaging member 54 is scalloped to facilitate slidingmovement of the sutures while preventing entanglement. While the numberof scallops can vary depending on the number of sutures used with theanchor, in the illustrated embodiment the suture-engaging member 54includes two scallops that defines three suture-seating grooves 55 a, 55b, 55 c. Thus, three sutures can be positioned around thesuture-engaging member 54, with each suture resting in a groove 55 a, 55b, 55 c. Each suture can thus be individually slid relative to thesuture-engaging member 54 without causing movement of an adjacentsuture. The scallops can also help maintain alignment of the sutures asthey extend through the anchor 50, thereby preventing entanglement. Aperson skilled in the art will appreciate that a variety of othertechniques can be used to help maintain alignment of the sutures,prevent entanglement, and/or facilitate sliding movement. For example,the suture-engaging member can include one or more pathways formedtherethrough, with each pathway being configured to receive a suture.

As previously indicated, in use the various suture anchors disclosedherein can be configured to receive one or more sutures, and to receivea driver for driving the anchor into bone to thereby anchor the sutureto bone. While various drivers can be used, FIGS. 6 and 7 illustrate twoexemplary embodiments of drivers that are particularly configured foruse with the suture anchors disclosed herein. Referring first to FIG. 6,as shown the driver 60 has a generally elongate shaft with a drive tip62 formed on a distal end thereof. The drive tip 62 has a shape and sizethat corresponds to the shape and size of the suture anchor. Inparticular, in the illustrated embodiment the drive tip 62 has ahexagonal cross-sectional shape that allows the tip 62 to be disposedwithin and to engage a hexagonal lumen formed in a suture anchor, suchas anchor 10 of FIGS. 1A-1D. The length of the drive tip 62 can vary,but preferably the length is maximized to provide enhanced surfacecontact between the drive tip 62 and the suture anchor. In an exemplaryembodiment, the drive tip 62 has a length that is configured such thatthe drive tip 62 can extend from the proximal end of the suture anchorand can terminate just proximal to the suture-engaging member. Asfurther shown in FIG. 6, the drive tip 62 can also include one or moresuture-seating grooves 64 formed therein and configured to seat theterminal ends of the suture so as to prevent engagement of the suturebetween the drive tip 62 and the suture anchor. While FIG. 6 illustratestwo opposing suture-seating grooves 64, the drive tip 62 can include anynumber of grooves, and the shape and size of each groove can varydepending on the quantity of sutures used with the suture anchor. Inanother embodiment, shown in FIG. 7, the driver 70 can be cannulated toallow the sutures to extend through the inner lumen 74 of the drive tip72 and through the elongate shaft of the driver, rather than along anexternal surface of the drive tip 72. A person skilled in the art willappreciate that a variety of other techniques can be used to facilitateengagement between a driver and a suture, and to allow free passage ofone or more sutures therebetween.

The particular quantity of sutures used with a suture anchor and drivercan depend on the size of the suture anchor and the driver, and inparticular on the diameter of the inner lumen of the suture anchor andthe size of the suture-engaging groove formed in the driver (for driver60) or the diameter of the lumen in the driver (for driver 70). Forexample, where the suture anchor has a relatively small inner lumen, thedriver will necessarily have a relatively small diameter and thus smallsuture-engaging grooves (for driver 60) or a small inner lumen (fordriver 70). It may therefore only be possible to use a single suturethat is positioned around the suture-engaging member on the sutureanchor, and that has two trailing ends extending through thesuture-receiving grooves in the driver (for driver 60) or through theinner lumen in the driver (for driver 70). While a single suture can besufficient to anchor tissue to bone, it is preferred to use more thanone, and more preferably two or three sutures. Thus, rather thanincreasing a size of the suture anchor and/or the driver, the presentinvention provides various exemplary techniques for utilizing twosutures with a suture anchor and driver that are configured to seat onlyone suture. This is particularly advantageous as the suture anchor canbe sized to be fully disposed within cortical bone, while the diameterof the inner lumen of the suture anchor and of the distal tip of thedriver are maximized to increase the torque failure rating. This alsoenables the anchor to be made from a broad range of materials, includingbrittle or weaker materials such as those previously disclosed herein.

The present invention also provides exemplary methods for anchoringtissue to bone. While a method is described in connection with attachingsoft tissue to bone, the methods and devices disclosed herein can beused in a variety of medical procedures for anchoring one structure toanother. In general, a bore is formed in bone of a patient. The diameterof the bore is preferably slightly less than the largest outer diameterof the suture anchor, and the length of the bore is preferably the sameas or slightly greater than a length of the suture anchor. The bore willextend fully through the cortical bone to allow the suture anchor to befully engaged through the thickness of the cortical bone. The bore canalso extend into the cancellous bone depending on the length of thesuture anchor. One or more sutures can be coupled to the suture anchorusing various techniques, including those disclosed in theaforementioned commonly-owned applications, and the distal tip of adriver can be inserted into the lumen in the suture anchor, for exampleas shown in FIG. 7. The trailing ends of the suture(s) can extendexternally along the driver or they can extend through an inner lumen ofthe driver. The driver can then be used to insert the suture anchor intothe bone tunnel. For example, where the suture anchor includes threadsformed thereon, the driver can be rotated to thread the suture anchorinto the bone hole. The threads will engage the bone hole therebypreventing removal of the suture anchor. Where the suture anchorincludes dual threads, the second thread will provide additionalfixation within the bone. By way of non-limiting example, FIG. 8illustrates the suture anchor 10 of FIGS. 1A-1C implanted in bone B, andhaving three sutures 80 a, 80 b, 80 c coupled thereto. As shown, thesutures 80 a-80 c extend around the suture-engaging member 14 and theyextend through the lumen of the anchor 10 and through a lumen in thedriver 70, thus allowing the driver 70 to drive the suture 10 into bonewithout interference from the sutures 80 a-80 c. In other embodiments,the driver can be used to tap the bone anchor into the bone hole, and aninterference fit, compression fit, and/or surface features, such as ribsor protrusions, formed on the suture anchor can be used to retain thesuture anchor within the bone hole. The driver can also optionally beused to impact a threaded suture anchor into the bone hole. The threadscan allow for later removal of the suture anchor.

Once the bone anchor is properly anchored within the bone hole, variousmaterials, such as those previously discussed herein, can be introducedthrough the driver and into or around the suture anchor. The driver canbe removed, and the trailing ends of the suture(s) can then be used toanchor soft tissue to the bone. For example, one or both trailing endsof the suture(s) can be attached to a needle to allow the needle to beused to thread the suture through tissue to be anchor to the bone. Thesuture(s) can be threaded through tissue either prior to or afterinsertion of the suture anchor into bone. Once the soft tissue isapproximated toward the bone, the trailing ends of the suture(s) can besecured together and the excess trimmed as is typical in thesesituations to complete the surgery. Once implanted, the cut-outextending into the inner lumen can allow materials, such as bone-growthpromoting materials, sealants, adhesives, etc., to be introduced thereinto facilitate fixation.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

What is claimed is:
 1. A method for anchoring suture to bone,comprising: coupling a suture to a suture anchor such that the sutureextends around a suture-engaging feature of the suture anchor andtrailing ends of the suture extend through an inner lumen extendingthrough the suture anchor and out of a proximal end of the sutureanchor, the inner lumen having a driver-receiving portion formedtherein, the driver-receiving portion extending along a substantiallongitudinal length of the suture anchor, the suture anchor including aconstant diameter portion extending along a partial longitudinal lengthof the suture anchor, and the suture anchor including a pointed,tapering distal tip extending distally from the constant diameterportion, the suture anchor having only one cut-out formed through asidewall thereof, and the one cut-out being located entirely in theconstant diameter portion proximal to the tapering distal tip; insertinga driver into the inner lumen such that a distal end of the driverengages a distal end of the driver-receiving portion; and rotating thedriver to thread the suture anchor into bone to secure the suture to thebone.
 2. The method of claim 1, wherein the suture anchor has first andsecond threads, each of the first and second threads extending from theproximal end of the suture anchor and toward a distal end of the sutureanchor, the first thread extending more distally than the second threadsuch that the first thread cuts through bone prior to the second threadcutting through bone in response to the rotation of the driver.
 3. Themethod of claim 2, wherein the rotation of the driver to thread thesuture anchor into bone causes the first and second threads to engagecortical bone and at least one of the first and second threads to engagecancellous bone.
 4. The method of claim 1, wherein the driver-receivingportion is defined by an enclosed shape of the inner lumen extendinglongitudinally along the suture anchor.
 5. The method of claim 1,wherein the inserting the driver into the inner lumen such that thedistal end of the driver engages the distal end of the driver-receivingportion includes the distal end of the driver contacting a substantialportion of a wall of the driver-receiving portion.
 6. The method ofclaim 1, wherein the suture-engaging feature is at a fixed axialposition relative to the suture anchor.
 7. The method of claim 1,wherein the distal end of the driver-receiving portion is locatedproximal to a proximal end of the cut-out.
 8. The method of claim 1,wherein the cut-out is located just proximal to the tapering distal tip.9. The method of claim 1, wherein a proximal-most end of the cut-out isproximal to the suture-engaging feature, and a distal-most end of thecut-out is distal to the suture-engaging feature.
 10. A method foranchoring suture to bone, comprising: coupling a suture to a sutureanchor such that the suture extends around a suture-engaging feature ofthe suture anchor and trailing ends of the suture extend through aninner lumen extending through the suture anchor and out of a proximalend of the suture anchor, the inner lumen having a driver-receivingportion formed therein, the driver-receiving portion extending along asubstantial longitudinal length of the suture anchor, the suture anchorincluding a pointed, tapering distal tip extending distally from aconstant diameter portion of the suture anchor that extends along apartial longitudinal length of the suture anchor, the suture anchorhaving a cut-out formed through a sidewall thereof, the suture-engagingfeature being defined by the cut-out, and the cut-out being locatedentirely in the constant diameter portion proximal to the taperingdistal tip; inserting a driver into the inner lumen such that a distalend of the driver engages a distal end of the driver-receiving portion;and rotating the driver to thread the suture anchor into bone to securethe suture to the bone.
 11. The method of claim 10, wherein thesuture-engaging feature is at a fixed axial position relative to thesuture anchor.
 12. The method of claim 11, wherein a proximal-most endof the cut-out is proximal to the suture-engaging feature, and adistal-most end of the cut-out is distal to the suture-engaging feature.13. The method of claim 10, wherein the driver-receiving portion isdefined by an enclosed shape of the inner lumen extending longitudinallyalong the suture anchor.
 14. A method for anchoring suture to bone,comprising: coupling a suture to a suture anchor such that the sutureextends around a suture-engaging feature of the suture anchor andtrailing ends of the suture extend through an inner lumen extendingthrough the suture anchor and out of a proximal end of the sutureanchor, the suture-engaging feature being at a fixed axial positionrelative to the suture anchor, the inner lumen having a driver receivingportion formed therein, the driver-receiving portion extending along asubstantial longitudinal length of the suture anchor, the suture anchorincluding a constant diameter portion extending along a partiallongitudinal length of the suture anchor, and the suture anchorincluding a pointed, tapering distal tip extending distally from theconstant diameter portion, the suture anchor having a cut-out formedthrough a sidewall thereof, a proximal-most end of the cut-out beingproximal to the suture-engaging feature, a distal-most end of thecut-out being distal to the suture engaging feature, and the cut-outbeing located entirely in the constant diameter portion proximal to thetapering distal tip; inserting a driver into the inner lumen such that adistal end of the driver engages a distal end of the driver-receivingportion; and rotating the driver to thread the suture anchor into boneto secure the suture to the bone.
 15. The method of claim 14, whereinthe driver-receiving portion is defined by an enclosed shape of theinner lumen extending longitudinally along the suture anchor.